Selected biological and behavioural risk factors associated with pulmonary tuberculosis

To measure the independent association of risk factors age, sex, smoking and alcoholism with pulmonary tuberculosis (TB) in terms of prevalence odds ratio (POR).

A community-based cross-sectional survey was conducted from June 2001 to December 2003. A total of 93945 individuals aged > or = 15 years selected from a random sample of villages in a district from South India were screened for pulmonary TB by chest symptoms and chest X-ray (MMR). Two sputum samples were collected (one spot and one early morning) from patients with chest symptoms and those with abnormal X-rays for examination by microscopy for acid-fast bacilli and by culture for Mycobacterium tuberculosis. Bacillary cases are bacteriologically positive cases diagnosed by either sputum smear or culture examination. In addition, data on exposure to tobacco smoking and alcohol consumption were collected from the male population only. All females were considered non-smokers and non-alcoholics.

A total of 429 bacteriologically positive cases were detected during the survey. The adjusted PORs (with 95%CI) for age, sex, smoking and alcoholism were 3.3 (2.7-4.1), 2.5 (1.9-3.3), 2.1 (1.7-2.7) and 1.5 (1.2-2.0), respectively.

Risk factors such as age, sex, smoking and alcoholism are independently associated with pulmonary TB. Risk factors age and sex show a stronger association than smoking and alcoholism.